The present invention generally relates to a method for preparing a solid milk product. More specifically, the present invention relates to a process for preparing a solid milk product having a moisture level of less than about 40 percent and a fat/protein ratio of less than about 2.5. The present invention also relates to a solid milk product which is a solid at ambient temperatures, has a moisture level of less than about 40 percent, and has a fat/protein ratio of less than about 2.5.
Dairy products such as liquid milk which are high in protein can form an important part of a nutritious diet. Unfortunately, many people do not generally consume liquid milk in sufficient quantities for a number of reasons. Thus, there has been considerable effort to prepare milk-based products in solid form which are more convenient to consume.
Barta, U.S. Pat. No.4,497,834 (Feb. 5, 1985) provided a simplified process for preparing a nutritious dairy-based product. This process involved condensing fatted or defatted milk to essentially the solids and moisture content desired in the final product, reducing the lactose content to below about 15 percent, and then cooking the mixture to produce, upon cooling, a gel-like material. If desired, fat could be added to a level of about 5 to 40 percent. The moisture content of the gel-like material was generally less than about 50 percent. However, to achieve low moisture levels, Barta was required to add significant levels of fat. Based on the reported examples in Barta, for example, a 48 percent moisture level product would have a fat/protein ratio of about 1.1; a 30 percent moisture level product would have a fat/protein ratio of about 6.2; and a 15 percent moisture level product would have a fat/protein ratio of about 19.6. Thus, Barta was only able to obtain relatively low moisture levels by significantly increasing the fat/protein ratios. Of course, such high fat/protein ratios result in a less desirable high-fat product, thereby significantly reducing the nutritional characteristics of the product.
Cillario, U.S. Pat. No. 4,298,625 (Nov. 3, 1981) provided a low moisture foam consisting of an oil-in-water emulsion prepared from edible fat, milk proteins, water, and optionally added sugars. Cillario was able to produce both xe2x80x9ccreamyxe2x80x9d (i.e., viscosity of about 400,000 cps) and xe2x80x9cpaste-like (i.e., viscosity of about 3,500,00 cps) products with moisture levels of about 17 to about 35 percent. Fat/protein ratios for both the creamy and paste-like products generally ranged from about 3.9 to about 12, with the xe2x80x9coptimumxe2x80x9d ratios reported at about 7 to about 7.5. Of course, such high fat/protein ratios result in a less desirable high-fat product, thereby significantly reducing the nutritional characteristics of the product.
It would be desirable, therefore, to produce solid milk products having low moisture levels as well as low fat/protein ratios. The present invention provides such solid milk products and methods for producing such solid milk products.
The present invention provides a method of preparing a solid milk product having a moisture level of less than about 40 percent and a fat/protein ratio of less than about 2.5, and preferably a moisture level of about 10 to about 30 percent and a fat/protein ratio of less than about 2.0. More preferably, the solid milk product has a fat/protein ratio of about 0.5 to about 1.5 and, even more preferably, about 1 to about 1.2. Generally, the solid milk product of the present invention has less than about 50 percent added sweetener (e.g., sugar), preferably about 12 to about 35 percent added sweetener, and more preferably about 25 to about 35 percent added sweetener. Generally, the total sweetener (i.e., added sweetener plus sugars added with other ingredients) is less than about 57 percent, preferably about 25 to about 52 percent, and more preferably about 25 to about 40 percent.
The present solid milk product is a high solids, low moisture, high-protein, shelf-stable milk product which is solid at ambient temperatures.
Thus, the present product can be conveniently transported and consumed by hand. Moreover, the present product can be produced in various formsxe2x80x94for example, solid bars, candy-type bars, cookies, cookies or bars with other ingredients (e.g., granola, grains, peanuts, other nuts, chocolate bits or chips, and the like), bite-sized forms or pieces, enrobed solid forms (e.g., coated with yogurt, yogurt-coated raisins, chocolate, and the like), shapes (e.g., animal, stars, letters), and the likexe2x80x94and can be produced with varying levels of sweetness. The present product can also be produced in an aerated form.
The present invention provides a method for preparing a solid milk product, said method comprising:
(1) blending an aqueous liquid, an edible fat, and concentrated milk protein source at a temperature of about 40 to about 95xc2x0 C. and under high shear conditions with a bulk peak shear rate of greater than about 950 secxe2x88x921 to form a first blend, wherein the blending continues until essentially all components in the first blend are hydrated and wherein the edible fat has a melting point less than about 50xc2x0 C;
(2) adding 0 to 1 percent of an emulsifier to the first blend either before or after essentially all components in the first blend are hydrated;
(3) adding, once essentially all components in the first blend are hydrated, 0 to about 3 percent of an emulsifying salt and 0 to about 1 percent TiO2 to form a second blend;
(4) continuing to heat the second blend to the temperature of about 65 to about 95xc2x0 C. under the high shear conditions until a homogeneous paste is obtained;
(5) pasteurizing the homogenous paste; and
(6) cooling the pasteurized homogenous paste to form the solid milk product,
wherein the relative amount of the aqueous liquid, the edible fat, and the concentrated milk protein source in the first blend are adjusted such that the solid milk product has a moisture level of less than about 40 percent and a fat/protein ratio of less than about 2.5 and wherein the solid milk product is a solid at ambient temperatures.
The present invention also provides a method for preparing a solid milk product having a moisture level of less than about 40 percent, said method comprising:
(1) blending an aqueous liquid, an edible fat, and concentrated milk protein source at a temperature of about 40 to about 95xc2x0 C. and under high shear conditions with a bulk peak shear rate of greater than about 950 secxe2x88x921 to form a first blend, wherein the blending continues until essentially all components in the first blend are hydrated and wherein the edible fat has a melting point less than about 50xc2x0 C.;
(2) adding 0 to about 1 percent of an emulsifier to the first blend either before or after essentially all components in the first blend are hydrated;
(3) added 0 to about 3 percent of an emulsifying salt and 0 to about 1 percent TiO2 to the first blend to form a second blend; wherein, if the moisture level of the solid milk product is to be greater than about 25 percent, the emulsifying salt and the TiO2 are added to the first blend either before or after essentially all components in the first blend are hydrated; and wherein, if the moisture level of the solid milk product is to be less than about 25 percent, the emulsifying salt and the TiO2 are added to the first blend after essentially all components in the first blend are hydrated;
(4) continuing to heat the second blend to the temperature of about 65 to about 95xc2x0 C. under the high shear conditions until a homogeneous paste is obtained;
(5) pasteurizing the homogenous paste; and
(6) cooling the pasteurized homogenous paste to form the solid milk product,
wherein the relative amount of the aqueous liquid, the edible fat, and the concentrated milk protein source in the first blend are adjusted such that the solid milk product has a moisture level of less than about 40 percent and a fat/protein ratio of less than about 2.5; and wherein the solid milk product is a solid at ambient temperatures.
In a preferred embodiment, the present invention provides a method for preparing a solid milk product, said method comprising:
(1) blending about 20 to about 50 percent condensed fat-free milk or sweetened condensed fat-free milk, about 10 to about 35 percent anhydrous milkfat, and about 8 to about 30 percent concentrated dry milk powder at a temperature of about 40 to about 95xc2x0 C. to form a first blend, wherein the blending continues until essentially all components in the first blend are hydrated;
(2) heating the first blend to a temperature of about 60 to about 95xc2x0 C. under high shear conditions with a bulk peak shear rate of greater than about 950 secxe2x88x921;
(3) adding 0 to 1 percent of an emulsifier to the first blend either before or after essentially all components in the first blend are hydrated;
(4) adding, once essentially all components in the first blend are hydrated, about 1 to about 3 percent of an emulsifying salt and about 0.4 to about 1 percent TiO2 to the first blend to form a second blend;
(5) continuing to heat the second blend to the temperature of about 65 to about 95xc2x0 C. under the high shear conditions until a homogeneous paste is obtained;
(6) pasteurizing the homogenous paste; and
(7) cooling the pasteurized homogenous paste to form the solid milk product,
wherein the solid milk product is a solid at ambient temperatures, has a moisture level of less than about 40 percent, and has a fat/protein ratio of less than about 2.5.
The present invention also provides a method for preparing a solid milk product, said method comprising:
blending an aqueous liquid, an edible fat, and concentrated milk protein source under moderate shear conditions with a bulk peak shear rate of greater than about 500 secxe2x88x921 to form a first blend, wherein the blending continues until essentially all components in the first blend are hydrated and wherein the edible fat has a melting point less than about 50xc2x0 C.;
(2) adding 0 to 1 percent of an emulsifier to the first blend either before or after essentially all components in the first blend are hydrated;
(3) adding, once essentially all components in the first blend are hydrated, 0 to about 3 percent of an emulsifying salt and 0 to about 1 percent TiO2 to form a second blend;
(4) heating the second blend to the temperature of about 65 to about 95xc2x0 C. under low to high shear conditions until a homogeneous paste is obtained;
(5) pasteurizing the homogenous paste; and
(6) cooling the pasteurized homogenous paste to form the solid milk product,
wherein the relative amount of the aqueous liquid, the edible fat, and the concentrated milk protein source in the first blend are adjusted such that the solid milk product has a moisture level of less than about 40 percent and a fat/protein ratio of less than about 2.5 and wherein the solid milk product is a solid at ambient temperatures.
The present invention also provides a solid milk product comprising about 15 to about 60 percent of an aqueous liquid (preferably condensed fat-free milk or sweetened condensed fat-free milk); about 8 to about 40 percent of an edible fat (preferably anhydrous milkfat); about 1 to about 45 percent of a concentrated milk protein source (preferably concentrated dry milk powder); 0 to about 3 percent of an emulsifying salt; 0 to about 1 percent TiO2; 0 to 1 percent of an emulsifier; and 0 to about 50 percent non-lactose sweetener, wherein the solid milk product is a solid at ambient temperatures, has a moisture level of less than about 40 percent, and has a fat/protein ratio of less than about 2.5. Preferably, the solid milk product has a moisture level of about 10 to about 30 percent and a fat/protein ratio of less than about 2. More preferably, the solid milk product has a fat/protein ratio of about 0.5 to about 1.5 and, even more preferably, about 1 to about 1.2.
Although the above-described methods provide excellent solid milk products, we have now discovered an even simpler production method which eliminates some of the heating steps and the use of high shear mixing. This simplified method is especially adapted for preparing solid ingredient-containing solid milk bars. Suitable solid ingredients for use in the present invention include cereals, cookies, trail mix, dried fruits, nuts, and the like as well as mixtures thereof. The present invention provides a simplified method for preparing a solid ingredient-containing solid milk product, said method comprising:
(1) blending an aqueous liquid, an edible fat, and concentrated milk protein source under low to moderate shear conditions to form a first blend, wherein the blending continues until essentially all components in the first blend are hydrated and the first blend forms a sticky white mass and wherein the edible fat has a melting point less than about 50xc2x0 C.;
(2) adding an emulsifying salt to the first blend either before or after essentially all components in the first blend are hydrated,
(3) adding sugar to the first blend either before or after essentially all components in the first blend are hydrated;
(4) adding a solid ingredient to the sticky white mass to form a solid ingredient and first blend mixture;
(5) blending the solid ingredient and first blend mixture under low shear conditions until the solid ingredient is coated with the first blend to form a second blend;
(6) placing the second blend into a container;
(7) baking the second blend in the container; and
(8) cooling the baked second blend to form the solid ingredient-containing solid milk product,
wherein the relative amounts of the aqueous liquid, the edible fat, the emulsifying salt, and the concentrated milk protein source in the first blend are adjusted such that the solid ingredient-containing solid milk product has a moisture level of less than about 40 percent and a fat/protein ratio of less than about 2.5 and wherein the solid ingredient-containing solid milk product is a solid at ambient temperatures.